Simulation of the Gas-Liquid-Solid Three-Phase Flow Velocity Field Outside the Abrasive Water Jet(AWJ) Rectangle Nozzle and Ellipse Nozzle

Abstract:

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Simulation of the flow field of the gas-liquid-solid three-phase flow outside the abrasive
water jet rectangle nozzle and ellipse nozzle is studied by the computed fluid dynamic
software-fluent, and the velocity field of the three-phase flow is obtained. The simulation result
expresses that the flow is expanded when it is out of the nozzle; the velocity of the flow is the
highest at the axis, which comes down by its side, the velocity of the flow is high at the beginning
then it is decreased because the flow is resisted by the air; the shape of the jet at the start is closed to
the geometry of the nozzle, then it is rounded in the external area; the velocity field outside the
ellipse nozzle is distributed evenly around the center. By plotting the velocity field of the rectangle
nozzle and the ellipse nozzle in the Y-Z section, it is expressed that the changing range of velocity is
enlarged with the increasing of distance offset the nozzle.

Abstract: An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other other applications. In particular, this type of pump is an essential element of an automotive engine to feed lubricant oil. We perform a theoretical analysis of the internal lobe pump whose main components are rotors. Usually, the outer is characterized by a lobe with elliptical and involute shapes, while the inner rotor profile is determined as the conjugate to the other rotor. Our integrated system, which is composed of three main modules, was developed through AutoLISP using AutoCAD. It generates a new lobe profile, and automatically calculates the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pumps to be more efficient.

Abstract: A kind of novel airfoil sail is proposed in this paper based on the research of traditional arc wing sails. The aerodynamic characteristic- the lift coefficient and drag coefficient is numerically calculated with FLUENT 6.0 and the results are verified by wind tunnel test. It is proved that the aerodynamic characteristic of the novel sail is much better than the arc wing sail.

Abstract: Using geothermal resources to instead of steam bled form the turbine steam to preheat feed water in a conventional Rankine cycle power station is also termed as geothermal aided power generation (GAPG), this offers a significant potential for the large-scale utilization of geothermal energy for power generation. GAPG enables the conversion of low temperature geothermal energy in the case of 90-260°C into power at a higher efficiency. In GAPG system, geothermal heat is used to preheat the feed water of power generation, instead of the extraction steam, thus the steam flows through the lower stages turbine have changed. In other words, the lower stage turbine works under off-design conditions. However, previous simulation models for the GAPG and solar aided power generation (SAPG), have not considered this turbine off-design operation. Under the off-design conditions, the isentropic efficiency of the turbine and pressure, temperature of each stage of turbines change which lead to the change of the output of turbine. In this paper, a modified thermodynamic model has been developed, considering these changes, which then can estimate the performance of a GAPG plant more accurately than the previous models. The results from various models are compared in this paper.

Abstract: Owing to the deficiency of machining non-circular curve by manual programming in CNC system, the universal macro-program of machining non-circular curve based on the ellipse curve in CNC turning of the FANUC system is developed by adopting analytical and inductive approach. The real application of machining ellipse and parabola curves are also proposed in this paper, which showed that the universal macro-program is flexible and convenient. The programming efficiency and quality is increased effectively while machining any other non-circular curve works.

Abstract: Generally, the shape index n is selected in a form when design the inlet-exhaust system using traditional super-ellipse method. Unfortunately, this selection process is time-consuming and not precise enough, so the cross-section designed by super-ellipse method may get distortions easily, which influences the inner flow and the total pressure of the inlet-exhaust system greatly. Associating the shape index n with the variation pattern of the inlet-exhaust cross-section, an improved super-ellipse method is developed to design the inlet-exhaust system. This method ensures the precision and uniqueness of shape index n for any cross-section in an adaptive way. The numerical simulation results show that the S-shape inlet designed using this method has high total pressure recovery coefficient and lower distortion coefficient, the S-shaped nozzle has high total pressure recovery coefficient and thrust coefficient.